Breezio - the Smart Fan Controller

Most consumer electronics, even simple devices like fans, are controlled by microcontrollers, enabling advanced features. However, microcontroller-based devices are often difficult to repair due to read-protection and specialized knowledge requirements. When these devices fail, they are often discarded, especially if replacement parts are unavailable.

Our project, the Breezio Smart Fan Controller, aims to address this issue by offering a low-cost, repairable solution that doesn’t rely on microcontrollers. Designed to upgrade conventional fans or replace faulty microcontroller-based controllers, this device combines analog and digital components for improved safety, energy efficiency, and user-friendliness. The Breezio controller provides a simple, affordable way to extend the lifespan of household appliances while reducing electronic waste.

Terminals & Connectors

1. 2-pin screw terminal – 1
2. 5-pin screw terminal – 1
3. 3-pin PCB mount wire clip with socket – 1
4. 4-pin PCB mount wire clip with socket – 1
5. Pin header (round/female) – 2
6. Pin header (female) – 2
7. Pin header (male) – 2

IC Bases

1. 6-pin IC base – 4
2. Round IC base, 8-pin – 3
3. Round IC base, 14-pin – 5
4. Round IC base, 16-pin – 2

ICs

1. MOC3041 opto coupler – 4
2. 4017 IC – 2
3. 74125N IC – 1
4. 7432N IC – 1
5. 7474N IC – 2
6. 7414N IC – 1
7. NE555 IC – 2
8. LM741 IC – 1

Resistors

1. 330R / 0.25W – 20
2. 2k2 / 0.25W – 5
3. 1k / 0.25W – 15
4. 560k / 0.25W – 1
5. 220k / 0.25W – 1
6. 100k / 0.25W – 1
7. 10k / 0.25W – 2
8. 12k / 0.25W – 3
9. 33k / 0.25W – 2
10. 1M / 0.25W – 1
11. 100R / 0.25W – 6
12. 100k Preset – 1

Capacitors

1. 0.47uF / 275V X2 capacitor – 2
2. 100nF / 50V capacitor – 2
3. 470uF / 16V capacitor – 1
4. 100uF / 16V capacitor – 2
5. 1uF / 16V capacitor – 6

Diodes ,Transistors & Triacs

1. 1N4148 diode – 3
2. BC547 transistor – 3
3. Z0607 800mA Triac - 4

Inductors

1. Inductor – 2

LEDs

1. 3mm LED (Blue) – 3
2. 3mm LED (Green) – 3
3. 3mm LED (Red) – 1

Switches

1. Tactile push button 6×6×9 mm – 6

Power & Others

1. PCB mount fuse holder – 1
2. 5V SMPS – 1
3. FR4 copper-clad board, double-side A4 – 1
4. FR4 copper-clad board, double-side A5 – 1
5. Ferric chloride – 200 g

The first stage of the project was to design the complete control circuit using Proteus. To keep the work organized, the fan controller was divided into smaller functional sections. Each section was designed and tested on its own before being combined into the final working circuit.

You can view the final Proteus circuit here:

Final Circuit Diagram:

https://drive.google.com/file/d/1ZA3iUQl2bkbzhGq8iMSTxzL0BbfLTTAQ/view?usp=sharing

1.Switch Interface

This part handles all user inputs such as power, speed, swing, timer, and natural breeze mode. Push buttons were connected through debouncing circuits and logic components so the control signals remained clean and stable.

2.Controller Section

This section manages the logic of the fan controller. It includes the speed sequence, the natural breeze generator, and the timer circuit. Components such as the 4017 decade counter, 555 timers, flip flops, and logic gates were used to coordinate how the fan behaves under each mode.

3.Power Circuit

The TRIAC-based power section was designed to switch the fan motor safely. Opto-isolators were added to provide electrical separation between the low-voltage control side and the 230 V AC supply. This increases safety and reduces noise.

A simplified block diagram of the complete system can be viewed here:

Block Diagram:

https://drive.google.com/file/d/1WHh1Jo0-r1EVavc2TJuGxypCTVTtWQCd/view?usp=drive_link

After completing the Proteus design, the next stage was to build the circuit on a project board. To keep the process reliable and easier to troubleshoot, each functional section of the fan controller was first assembled and tested on its own before being combined into the full system.

1.Build Each Section Separately

Begin by constructing the switch interface, controller logic, and power circuit as individual units. Assemble each section on a breadboard or project board and verify its function. This step-by-step approach helps isolate errors and ensures every part works correctly before moving forward.

2.Test the Function of Each Unit

Power each section and observe its outputs. Check the button response, logic signals, timer behaviour, and TRIAC triggering separately. Only move to the next stage after confirming the section is operating as designed.

3.Solder the Stable Sections on Vero Board

Once the switch interface and power circuit have been tested and confirmed, solder these two parts onto a vero board. These sections benefit from permanent connections because they carry the most frequently used inputs and deal with higher voltages.

4.Connect the Subcircuits to the Main Controller

After soldering, connect the verified modules to the main controller circuit. Ensure that reference lines such as ground and signal outputs are properly aligned.

5.Use Suitable Wiring for Reliable Connections

For better stability and reduced noise, avoid using loose jumper cables. It is recommended to use a Solderless Project Board Jumper Wire Kit or telephone cable wire to create neat and secure connections between each section.

By following this staged method, the complete fan controller can be built with fewer errors, stronger connections, and easier troubleshooting during assembly.

After confirming that the breadboard prototype worked correctly, the next stage was to design the printed circuit board. To keep the controller safe, modular, and easy to service, the PCB was divided into three separate boards, each handling a specific function.

1.Switch Interface Board

This board contains all control switches and indicator LEDs. It was placed as a dedicated module so the user interface could be mounted neatly on the front panel. The button traces were kept short and isolated from the power section to reduce noise.

2.Main Controller Board

This board holds the complete control circuitry, including counters, timers, flip flops, and logic gates. The layout was arranged to follow the same flow as the schematic, allowing clean routing between the speed control, timer, and breeze-mode sections. Clear labeling and spacious routing were used to make troubleshooting easier.

3.Power Circuit Board

This board contains the 230 V to 5 V converter, the TRIAC driver stage, and the opto-coupler interface. An EMI filter was included at the mains input, which is essential for reducing electrical noise and improving safety. High-voltage and low-voltage areas were kept well separated with proper clearances. Wider copper tracks were used for high-current paths.

4.Interconnecting the Boards

The user interface board and the controller board were connected using pin headers, allowing the two modules to be separated during assembly or repair.

The controller board and power board were connected using 5-pin and 3-pin PCB-mount wire clips with sockets, providing a firm and safe connection between the low-voltage logic and the mains switching section.

By dividing the system into three boards, each part becomes easier to assemble, test, and replace if needed. This modular layout also improves safety during construction and helps protect the low-voltage logic from interference coming from the mains circuitry.

Once the PCB layouts were completed, there were two options for producing the boards: ordering them from a PCB manufacturer or making them at home. Both methods are suitable for this project.

Option 1: Order PCBs Using Gerber Files

The PCB layouts can be exported directly from EasyEDA as Gerber files.

These files can be uploaded to any PCB manufacturing service.

This option provides high-quality, professionally finished boards with plated through-holes and solder masks.

Option 2: Make the PCBs at Home

Home fabrication is practical for small-scale builds and testing.

The process is divided into single-sided and double-sided PCB methods.

Single-Sided PCB Fabrication

1. Print the PCB Layout

• Use a toner printer and thin photo paper.

• Cut the printed layout close to the circuit edges to help with alignment.

2. Prepare the Copper Board

• You can use PP copper board, but FR4 copper board is recommended for better strength and durability.

• Cut the board to size using a hacksaw.

• Smooth the edges with sandpaper or a grinding wheel to remove burrs.

• Clean the copper surface until it shines. Metal polish such as Brasso works well.

• A clean, bright surface helps the toner transfer properly.

3. Transfer the Toner to the Board

• Place the printed layout on the copper surface with the toner side touching the copper.

• Align it carefully so the traces match the board size.

• Use a household iron set to maximum heat and press firmly over the paper.

• Heat helps the toner melt and bond to the copper.

• Allow the board to cool, then peel off the photo paper.

4. Repair Imperfect Toner Areas

• If some traces did not transfer fully, repair them with a permanent marker or correction fluid.

• Make sure all tracks are continuous and no gaps remain.

Double-Sided PCB Fabrication

Creating a double-sided PCB requires careful alignment so that the top and bottom copper layers match perfectly. The steps below describe the toner-transfer method used for this project.

1. Print the PCB Layout

• Use a toner printer and thin photo paper for both layers.

• The top layer must be mirrored before printing so it transfers in the correct orientation.

• Trim both printed sheets close to the circuit outline to make alignment easier.

2. Prepare the Copper Board

This step is the same as the single-sided method:

• Use FR4 copper board for best strength.

• Cut to size with a hacksaw.

• Smooth all edges using sandpaper or a grinding tool.

• Clean the copper surfaces thoroughly until shiny using Brasso or another metal polish.

• A clean surface ensures proper toner transfer.

3. Align the Two Printed Layers

Double-sided alignment is the most important step.

1. Cut both printed papers neatly around the circuit outline.
2. Place a LED panel light on your work surface.
3. Stick the bottom layer on the LED panel with the toner side facing upward.
4. Cover the unused areas of the LED panel with an A4 sheet to protect your eyes from the light.
5. Turn on the LED panel. The tracks and pads of the bottom layer will become clearly visible through the paper.
6. Take the top layer (mirrored print), place it toner side down, and carefully align it with the bottom layer using the light to ensure all pads match on both sides.
7. Once alignment is perfect, secure the two sheets together using masking tape, leaving the middle area open so the copper board can slide inside later.

The purpose of this step is to create a small “pouch” with both printed layers aligned around the copper board.

4. Insert the Board and Transfer the Toner

1. Slide the cleaned copper board into the space between the two aligned papers.
2. Gently remove the bottom sheet from the LED panel without disturbing the alignment.
3. Iron the first side thoroughly at maximum heat.
4. Flip the board and iron the other side as well.
5. Allow the board to cool completely.
6. Peel off both photo papers.

5. Inspect and Repair

• Check alignment between top and bottom pads.

• If small gaps or broken traces appear, repair them with a permanent marker or correction fluid.

• Ensure that all pads and tracks on both sides are ready for etching.

After the toner transfer is completed and both layers have been inspected and repaired, the next stage is to remove the unwanted copper. This is done by etching the board in a chemical solution. Proper safety precautions are essential during this process.

1. Prepare the Etching Solution

• Ferric chloride is recommended and commonly used.

• Mix it in a plastic or glass container.

• Do not use metal containers, as ferric chloride will react with metal.

2. Place the PCB in the Etchant

• Gently place the PCB into the ferric chloride solution with the copper side facing upward.

• For double-sided boards, make sure both sides are fully submerged.

• Move the tray slowly back and forth to help the etchant work evenly.

• Avoid touching the solution directly.

3. Monitor the Etching Process

• The exposed copper will gradually dissolve, leaving only the toner-covered tracks.

• Check the board every few minutes.

• Do not over-etch, as this can thin the traces and weaken the board.

• When all unwanted copper is removed, take the board out of the solution.

4. Rinse the Board

• Rinse the PCB thoroughly under running water to remove all ferric chloride.

• Dry it with tissue or a clean cloth.

5. Remove the Toner Mask

• Use thinner to wipe off the toner from the copper tracks.

• The final copper patterns should now be visible, clean, and shiny.

6. Disposal and Safety

• Do not pour used ferric chloride into sinks or drains.

• Clean your work area and wash your hands after handling chemicals.

7. Apply a Protective Coating (Anti-Oxidation Layer)

To prevent the copper from oxidizing before soldering, a thin protective layer is applied.

a. Prepare the Resin Coating

• Take clear resin (natural resin or synthetic rosin).

• Crush it into a fine powder.

• A household blender can be used for better results.

• Dissolve the powdered resin in thinner until it becomes a thin liquid.

• The mixture should flow easily like light varnish.

b. Apply the Coating

• Use a small art brush to apply the resin solution evenly across the copper surface.

• Check carefully to ensure every copper area is fully covered.

• Apply a second coat if needed.

• The final coating should be moderately thick, forming a smooth, even layer.

c. Drying

• Allow the board to dry completely at room temperature.

• Once fully dried, the PCB is ready for drilling.

d. Why This Layer Is Important

• It prevents the copper tracks from turning dull or oxidizing.

• The layer does not interfere with soldering.

• When soldering, the heat from the iron melts and removes the resin automatically, giving clean solder joints

Once the etched board has been cleaned and coated with the protective resin layer, the next step is drilling the holes for components and connectors. Accurate drilling ensures components fit properly and remain firmly mounted during soldering.

1. Tools and Drill Bits

A small hand drill or a mini rotary drill is suitable for PCB work.

Use the following drill bit sizes:

• 0.8 mm – for most component leads (resistors, diodes, capacitors, IC sockets)

• 0.9 mm – for pin headers

• 1.0 mm – for PCB-mount connectors, screw terminals, and thicker component pins

Make sure the bits are sharp to avoid cracking the PCB.

2. Drilling Procedure

1. Place the PCB on a flat wooden surface or drilling pad to prevent damage.
2. Start with the 0.8 mm bit and drill all standard component holes.
3. Switch to the 0.9 mm bit and drill the areas for pin headers.
4. Use the 1.0 mm bit for connectors and any components with thicker leads.
5. Keep the drill vertical to avoid angled holes.
6. After drilling, gently brush off dust and check that every hole is clean and open.

3. Inspect the Board

• Insert a few components to confirm the hole alignment.

• Ensure no copper pads lifted during drilling.

• If a hole is slightly misaligned or tight, widen it gently with the correct bit.

Your drilled PCB is now ready for the next stage, which is soldering and assembling the three-board system.

With all holes drilled and the boards prepared, the next stage is soldering the components and connecting the three PCB modules: the switch interface board, the control board, and the power board. Careful soldering ensures reliable operation and long-term durability.

1. Solder All Components to Each Board

• Begin by soldering the lowest-profile components first such as resistors and diodes.

• Then solder IC sockets, capacitors, transistors, and connectors.

• Ensure all joints are shiny and smooth.

• Inspect for cold solder joints or accidental bridges between pads.

The resin protection layer applied earlier will melt easily during soldering, so it will not interfere with the joints.

2. Connect the Switch Interface Board to the Control Board

• Use pin headers to link the switch interface to the control circuit.

• Solder the pins on both sides, ensuring a straight and solid connection.

• This allows easy removal or replacement of the switch interface in the future.

3. Connect the Control Board to the Power Board

• Use PCB-mount wire connectors (5-pin and 3-pin clips) for safe and reliable connections between the control board and the power board.

• Solder the wires directly to the power board, since it carries mains-related circuitry.

• Solder the connector side to the control board, allowing it to detach easily for testing or servicing.

This modular wiring method also keeps high-voltage and low-voltage sections separated for better safety.

4. Timer Calibration (R14 Adjustment)

To obtain the correct timing value for the timer circuit, the reference voltage at pin 2 of the 741 must be set to 2.5 V.

• Power up the circuit (the switch interface board is not required for this step).

• Measure the voltage at pin 2 of the 741 IC.

• Adjust the R14 preset slowly until the voltage reads 2.5 V.

• This ensures accurate operation of the timer function.

Perform this calibration carefully to avoid overshooting the desired voltage.

Once soldering and calibration are complete, the board assembly is finished and ready for wiring the fan, indicators, and enclosure.

After assembling all three boards, the final stage is to mount the controller inside an enclosure, connect the fan wiring, and test all functions. A sample enclosure design is provided, but you may edit it or create a new one to match your fan model.

1. Enclosure

• Choose or design an enclosure that fits comfortably on your fan housing.

• The sample enclosure can be used directly or modified to suit your preferred shape and size.

• Ensure there is proper spacing between the switch interface, controller board, and power board.

• Provide ventilation slots if needed to allow heat from the TRIACs to escape.

• Mount the switch interface board so the buttons and LEDs align with the front panel.

2. Wiring the System

a. Mains Connection

• The mains supply should be wired directly into the power board.

• Install a 0.5 A fuse in the fuse holder for safety.

• Double-check all high-voltage connections for tightness and insulation.

b. Fan Motor Connections

• The fan motor and swing motor outputs connect to the power board terminals.

• Both motors share a common supply.

• Connect this common supply to the Live OUT terminal on the power board.

• The control board will trigger the TRIACs through the opto-isolators to regulate the speed and swing.

3. Testing the Controller

Once wiring is complete, power up the unit and verify each function.

Function Summary

• Standby: When power is applied, the standby LED switches ON.

• Power Button: Pressing the ON button turns OFF the standby LED and lights the ON indicator.

• Speed Control:

– Each press cycles through Low → Mid → High → Off.

• Swing Control:

– First press turns swing ON.

– Second press turns swing OFF.

• Natural Breeze Mode:

– Pressing the Natural button activates the random speed-change pattern to simulate natural wind.

• Timer Operation:

1. Use the timer select button to choose a time (10 min, 30 min, or 1 hour).
2. Each LED corresponds to the selected time.
3. After selecting, press the Timer ON button to start the countdown.

Confirm that all LEDs, outputs, and motors respond correctly.

4. Troubleshooting Guide

• Standby LED not turning ON

– Check mains input.

– Check the 0.5 A fuse.

• Timer not activating

– Measure pin 2 of the 741 IC.

– Ensure it is adjusted to 2.5 V using the R14 preset.

• Some speeds not working

– Check the opto-couplers.

– Check the TRIACs for correct operation.

• Swing motor not working

– Inspect the swing opto-coupler and TRIAC.

– Check wiring to the swing motor.

• Buttons not responding

– Make sure the pin-header connection between the switch interface and control board is tight and properly aligned.

Your Breezio Smart Fan Controller is now fully assembled, wired, and tested.

The Breezio Smart Fan Controller brings together a fully repairable, microcontroller-free design that upgrades almost any household fan. By dividing the system into three separate PCBs—the switch interface, the controller, and the power module—the project becomes easier to build, test, and maintain. Each part can be replaced or modified without affecting the rest of the unit, making the controller long-lasting and user-friendly.

Through the design process, the circuit was first simulated in Proteus, then prototyped on project boards, and finally converted into well-structured PCBs. Whether you chose to manufacture the PCBs professionally using Gerber files or create them at home with the toner-transfer method, each approach leads to a clean and reliable final system.

The enclosure can be customized to suit your fan model. Wiring the mains supply, connecting the fan motor and swing motor, and testing all functions ensure that the controller works exactly as intended. Speed control, swing mode, natural breeze mode, and the timer feature all operate smoothly once calibrated. Troubleshooting tips help identify common issues quickly.

Safety Notes

Even though the controller uses opto-isolation, it still handles 230 V AC mains power, which can be dangerous. Keep these precautions in mind:

• Always disconnect the fan from mains before soldering or wiring.

• Double-check all high-voltage connections for insulation and tightness.

• Use the 0.5 A fuse on the power board to protect against faults.

• Ensure the enclosure fully covers all live parts and has no exposed conductors.

• Never touch the power board while it is energized.

If you are not confident working with mains electricity, consult a qualified technician.

All design resources for the Breezio Smart Fan Controller are included in a single ZIP file.

This package contains:

• Full Proteus schematic

• Block diagram

• PCB layouts (top and bottom layers)

• Gerber files for manufacturing

Everything needed to build or modify the controller is inside this archive.

📦 Download the Complete Project ZIP File

Link: https://drive.google.com/file/d/1nXy5Bf92sFrK_Ti31rRHznxw_gPdN2I3/view?usp=drive_link